Manufacture of artificial spinnable material



similate the properties of wool.

Patented June 23, 1942 s PATENT OFFICE MANUFACTURE OF ARTIFICIAL SPINNABLE MATERIAL Angelo DAmbrosio and Arnaldo Corbellinl,

Mllan, Italy No Drawing. Application March 9, 1938, Serial No. 194,984. In Italy November 26, 1936 16 Claims. (01; 106-127) This invention relates to the manufacture of artificial material by coagulation from mixed solutions of protein and viscose and enables articles such as spinnable filaments'to be made from such solutions whilst utilizing in part already existing plants for the manufacture of artificial cellulosic filaments.

It is known that for a number of years attempts have been made to produce artificial spinnable material containing some protein substances and possessing woolor silk-like properties. -It is well known, however, that the materials of this character so far produced have not given satisfactory results due. to theirdeficient mechanical and chemcal properties and their high cost.

Among the cheapest protein materials the keratinous substances such as constitute horn, hooves, nails, and hair, and other proteins such as gluten, ossein and the like, which are insoluble in dilute alkali, have been considered and have attracted the attention of many investigators. The substances of the first of said groups have in particular been considered because they as- The said protein substances were dissolved in different solvents, having generally an alkaline or acid character, but the results were always unsatisfactory, mainly because the filaments obtained from these solutions did not possess suftion is only possible by packing the mass in aficient strength or did not meet the requirements of practical utilization.

A difilculty arising in connection withproteins insoluble in dilute alkali is that the use of strong alkali causes decomposition of the protein.

Thus according to the process described in the British specification No, 55,623 of 1925 the keratin, fibroin or the like is or are dissolved by means of caustic alkali and cellulose and carbon disulphide'are added. By this processjbecause caustic alkali is employed, the molecules of the protein substance are subject to a strong decomposition, which is much more substantial-than when sodium sulphide is employed as solvent, as

recently proposed and which acts mainly as reducing and not as hydrolizing agent.

In an article by Dr. Grafe published in the journal Angewandte Chemie No. 20, dated May 16, 1936, on page 306, it is stated that it is impossible to obtain a viscous solution of keratin by dissolving completely wool fibres in sodium sulphide. In this article it is stated: By the'action of 50 gms. of crystallized sodium sulphide and 115 gms. water on 100 gms. wool a viscous mass is obtained which still contains numerous undis- V keratin.

Due to the viscosity and the high degree of swelling of the undissolved parts in such a case, all known methods of filtration fall short. Filtrapress filter cloth and compressing same in a cylinder closed at one side, an exactly fitting piston being pressed against the mass by means of a screw press. Having tried to produce artificial filaments from the keratin solution thus obtained, it was stated that, even when it was possible to spin the dissolved keratin, rough fibers were obtained 'which-fshow a very low strength when still Wet and a very'low elasticity after drying.

' An'object of this invention is an improved process of producing a solution of viscose and protein for the manufacture of artificial materials by coagulation, the said process being of particular advantage where the source of the protein isa material insoluble in dilute alkali, such as keratinous materials presenting the difliculties described in the article already referred to, gluten and ossein.

Further objects of the invention relate to the subsequent steps involved in obtaining an artificial material such as a filament from such a solution.

We have found that a satisfactory viscoseprotein solution for the manufacture of artificial materials can beobtained, with proteins insoluble in dilute alkali by preparing in a known manner a paste of the keratin or other protein, and an alkalin sulphide, by homogenizing the same thoroughly and by leaving this paste for a suificiently long time at a temperature of 15-30 C., in order to obtain a practically complete protein liquor with the slightest possible decomposition of the protein molecules. By a suitably longer kneading operation, the maturing treatment at 15-30 may be suitably shortened or even eliminated. The keratin or other protein liquor thus obtained cannotbe filtered alone, but when mixed with a vis-,

cose solution already mature for spinning it constitutes together with this latter a mixed solution which unexpectedly is practically free from undissolved keratin parts and can be easily filtered and spun,

The proteinliquor which can be mixed in any suitable proportion with a viscose solution, thus forming viscous mixed solution, is prepared as follows:

The protein material insoluble in dilute alkali (for example, horn. hooves, nails, hair, or wool waste), is milled into a fine powder. This powder is treated in suitable l-zneaders and mixers with a solution containing 5-15 per cent of sodium sulphide. Depending on the kind of raw materials employed, for each 100 parts of protein material to be dissolved, 150-300 parts of this sulphide solution are usually employed. The viscous paste obtained by kneading and mixing the powdered protein with the solution of sodium sulphide is allowed to become fluid at a temperature of 15-30 C. for about l-to 15 hours, according to the more or less thorough mechanicalmixing and kneading and to the temperature employed, in which time it becomes substantially homogeneous. After this time a nearly complete dull-green liquor is obtained.

The keratin thus rendered fluid is thor-. oughly mixed with a viscose solution, for example cellulose xanthogenate, already mature for spinning, in which it is completely dissolved. This mixed solution can be, rapidly filtered through the usual filter presses whereas the original keratin liquor was practically unfilterable. The mixing with cellulose xanthogenate can be effected in any proportion and it is practically possible to obtain mixed filaments or otherarticles having a protein content of say 90 per cent and more.

For convenience the application of the invention to the production and spinning of filaments will be considered.

Before spinning, the mixed solution obtained according to the invention is deaerated or degassed under vacuum in the usual manner.

Our spinning and coagulation is effected cxactv ly as in the case of viscose silk.

The next step is the rendering insoluble or tanning of the filaments, which is effected as follows:

The filaments are first washed thoroughly with water in order to eliminate the acid coagulating liquor and are treated with a tanning liquid consisting preferably of an aqueous solution containing about 8 per cent of formic aldehyde with the addition of 4-6 per cent of alum and some lactic acid, and the whole is heated for a short time to 45-50 and then allowed to cool at room temperature, until the reaction is completed.

It is possible also to effect all the tanning at room temperature, or also to heat the tanning liquid in the last phase of the reactions. According to the procedure adopted the filaments show different characteristics.

It is also possible to avoid the employment of the organic acid if the filaments are not thoroughly washed after coagulation.

Particular advantageous characteristics are imparted to the filaments if same are dried after sive materials, especially those of the character indicated which are insoluble in weak alkali and from which it has not hitherto been thought possible to produce a solution capable of being filtered.

' It is 'to be understood that the process just described is given only by way of example and can undergo numerous changes without departing from the spirit of the invention; thus, for instance, other additions to the sulphide solution can be made, and furthermore, as constituents of the tanning solution, instead of formic aldehyde other similarly acting reagents as acetic aldehyde, acrolein, furfurol and the like can be employed, and instead of alum, aluminium sulphate or the like.

Likewise it i possible to precipitate, within or on the mixed filaments produced according to the invention, suitable insoluble, protecting or tarnishing or like substances in like manner as with artificial cellulose silk.

We claim:

1. The process of preparing a mixed solution of keratin and viscose for the manufacture of artificial material by coagulation, which comprises treating a keratinous material, in a finely powdered state, with an alkali sulphide solution, converting the mass to a fluid condition by a treatment which includes thorough mixing and mechanical kneading, and thereafter mixing the fluid mass with a viscose solution.

2. The process of preparing a mixed solution of keratin and viscose for the manufacture of artificial material by coagulation, which comprises treating a keratinous material, in a finely powdered state, with an alkali sulphide solution, converting the mass to a fluid condition by a treatment which includes thorough mixing and mechanical kneading, thereafter mixing the fluid 4. The process of preparing a mixed solution of keratin and viscose for the manufacture of artificial material by coagulation, which comprises thoroughly mixing and mechanically kneading a keratinous material, in a finely powdered state, with an alkali sulphide solution in the proportion of parts of keratinous material to to 300 parts of a 5 to 15% aqueous solution of an alkali sulphide, causing the mass to attain a fluid condition, thereafter mixing the fluid mass with a viscose solution, and filtering the resultant solution.

5. The process of preparing a mixed solution of keratin and viscose for the manufacture of artificial material by coagulation, which comprises thoroughly mixing and mechanically kneading a keratinous material, in a finely powdered state, with an alkali sulphide solution, in the proportion of 100 parts of keratinous material to 150 to 300 parts of a 5 to 15% aqueous solution of an alkali sulphide, maturing the mass at temperatures within the range of 15 to 30 C. to attain a fluid condition thereof, thereafter mixing the fluid mass with a viscose solution, and filtering the resultant solution.

6. The process of preparing a mixed solution of keratin and viscose for the manufacture of artificial material by coagulation, which comprises treating a keratinous material: insoluble in weak alkali, in a finely powdered state, with an alkali sulphide solution, converting the massto a fluid condition by a treatment which includes thorough mixing and mechanical kneading, and thereafter mixing the fluid mass with a viscose solution.

7. The process of preparing a mixed solution of keratin and viscose for the manufacture of artificial material by coagulation, which comprises thoroughly mixing and mechanically kneading a keratinous material insoluble in weak alkali, in a finely powdered state, with an alkali sulphide solution, maturing th mass at temperatures within the range 15 to 30 C. to attain a fluid condition thereof, thereafter mixing the fluid mass with a viscose solution, and filtering the resultant solution.

8. The process of preparing a mixed solution of keratin and viscose for the manufacture -of artificial material by coagulation, which comprises thoroughly mixing and mechanically kneading a keratinous material insoluble in weak alkali, in a finely powdered state, with an alkali sulphide solution in the proportion of 100 parts a of keratinous material to 150 to 300 parts of a to aqueous solution of an alkali sulphide,

-maturing the mass at temperatures within the range 15 to C. to attain a fluid condition thereof, thereafter mixing the fluid mass with-a viscose solution, and filtering the resultant solution.

9. A process of manufacturing artificial materials, comprising in combination the steps of preparing a keratin viscose solution in the manner claimed in claim 6, thereafter degassing the solution and coagulating the same 'in a wet coa ulation bath, and subsequently tanning the coagulated material in a bath containing a keratin insolubilizing agent, a. water soluble aluminium salt, and a weak organic acid, the tanning being efiected in part at room temperature and in part at temperatures of 45 to 50 C., and the tanned filaments being washed and then dried at a temperature under 100 C.

10. A process of manufacturing artificial materials, comprising in combination the steps of preparing a keratin viscose solution in the manof a keratin coagulating aldehyde, 4 to 6% ofv alum, and -a weak acid, washing the material,

with water and then drying first at a temperatil ner claimed in claim 6, thereafter degassing the solution and coagulating the same in a wet coagulation bath; and subsequently tanning the coagulated material in a bath containing a keratin insolubilising agent, a water soluble aluminium salt, and a weak organic acid, and washing the material with water and then drying first at a temperature under 100 C. and finally at a temperature of 100 to 105 C.

12. A process of manufacturing artificial materials, comprising in combination the steps of preparing a keratin viscose solution in the manner claimed in claim 6, thereafter degassing the ture under C. and finally at a temperature solution and coagulating the same in a wet coagulation bath, and subsequently tanning the coagulated material in a bath containing a keratin insolubilising agent, a water soluble aluminium salt, and a weak organic acid, the tanning being effected by first treating the material in the tanning bath then raising the tanning bath to a temperature of 45 to 50 C., and then allowing the bath to cool slowly, the filaments being left in the bath at room temperature until the tanning is complete.

13. The process of preparing a mixed solution of keratin and viscose for the manufacture of artificial material by coagulation which comprises treating a keratinous material, in a finely powdered state, with a sodium sulphide solution,

converting the mass to'a fluid condition by a treatment which includes thorough mixing and mechanical kneading, and thereafter mixing the fluid mass with a viscose solution.

14. The process of preparing a mixed solution of keratin and viscose for the manufacture of artificial material by coagulation, which come prises treating a keratinous material, ina finely powdered state, with a sodium sulphide solution, converting the mass toa fluid condition by a treatment which includes thorough mixing and mechanical kneading, thereafter mixing the fluid mass with a viscose solution, and filtering the resultant solution. 7

15. The process of preparing a mixed solution of keratin and viscose for the manufacture of artificial material by coagulation, which comprises treating a keratinous material insoluble in weak alkali, in a finely powdered state, with a sodium sulphide solution, converting the mass to a fluid condition by a treatment which includes thorough mixing and mechanical kneading, and thereafter mixing the fluid mass with a viscose solution.

16. The process of preparing a mixed solution of keratin and viscose for the manufacture of .sulphide solution, maturing the mass to attain a fluid condition thereof. thereafter mixing the mass with a viscose solution, and filtering the fluid resultant solution.

ANGELO DAMBROSIO. ARNALDO CORBELLINI. 

